1. Doskocil Petmate Lebistro Portion Control Automatic Dog Cat Feeder
2. Petmate Le Bistro Feeders
These Petmate Le Bistro Feeders are gravity-operated. If your cat has a need for "free feeding" of dry food, these feeders will guarantee a ready supply. Sizes vary from two to twenty pound capacities, for multiple-cat households.3. Lentek Pet Dish Six Day Automatic Pet feeder
This is a round feeder with six doors that can be programmed to automatically open at pre-set intervals. It is advertised to hold either dry or canned food, with two freezer packs for keeping canned food fresh.
I would question using a device like this for occasions where the cat's owners are away on lengthy trips. Cats have other needs, including regular litter box maintenance, as well as just checking on their welfare. However, it might be useful for cat owners who work long hours and want their pets to have moist food during the day.
Operates on one 9-Volt battery (not included)
4. CatMate Automatic Feeder
Features two compartments with an ice pack for keeping canned food fresh for up to 48 hours. You can set the timer to open each can separately, or both at once, if you're feeding two cats. Timer can be set for as far as 96 hours ahead.
I would advise the same cautions about using this kind of feeder when taking lengthy trips. It might make it more convenient for your pet sitter who only visits once a day, but be sure you have a pet sitter



